Modifying POSS compounds

ABSTRACT

Method is provided for controlling the stereo chemistry of functionalities or X groups to exo or endo positions on a polyhedral oligomeric silsesquioxane (POSS) compound by adding certain reagents to said X groups to change one or more positions thereof to endo or exo. Also provided are the POSS species formed by the above inventive method. Method is also provided for inserting a ring substituent into a POSS compound. Also provided are the POSS species formed by such inventive method.

DOMESTIC PRIORITY

This CIP application claims the benefit of parent application, Ser. No.09/258,248, filed in the USPTO on Feb. 25, 1999 and now abandoned, inthe name of the inventors herein as well as provisional application No.60/076,817, filed Mar. 3, 1998.

STATEMENT OF GOVERNMENT INTEREST

The invention described herein may be manufactured and used by or forthe Government for governmental purposes without the payment of anyroyalty thereon.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to modifying polyhedral oligomeric silsesquioxane(POSS) compounds, particularly methods for controlling the stereochemistry of functionalities or X groups to desired positions on POSScompounds and also to methods for inserting one or more ringsubstituents, other than silicon, into a POSS compound.

2. Description of Related Art

Recent art in the silsesquioxane field has taught processes for thechemical manipulation of the organic functionalities (substituents,e.g., denoted by R) contained on the silicon oxygen frameworks ofpolyhedral oligomeric silsesquioxanes (POSS). While these methods arehighly useful for varying the organic functionalities contained on POSSmolecules, they do not offer the ability to cleave and/or manipulate thesilicon-oxygen frameworks of such compounds. Thus, these methods are ofno utility for transforming the multitude of readily availablepolyhedral oligomeric silsesquioxanes systems into useful compounds thatcan be subsequently utilized for a multitude of catalysis and materialapplications.

Earlier art has reported that bases (e.g. NaOH, KOH, etc.) could be usedto (1) catalyze the polymerization of polyhedral oligomericsilsesquioxanes into partly networked resins, (2) convertpolysilsesquioxane resins into discrete polyhedral oligomericsilsesquioxane structures and (3) catalyze the redistribution ofselected fully condensed polyhedral oligomeric silsesquioxane structuresinto other related fully condensed polyhedral oligomeric silsesquioxanestructural types. While the base assisted/catalyzed method does affordthe manipulation of silicon-oxygen frameworks, it is not effective atselectively producing incompletely condensed frameworks from completelycondensed species. This limitation results from the intolerance of thesilicon-oxygen framework present in polyhedral oligomericsilsesquioxanes to base.

Accordingly there is need and market for a method for opening and/orsubstituting on POSS rings that overcomes the above prior artshortcomings.

There has now been discovered a method that rapidly and effectivelyopens the silicon-oxygen frameworks of POSS compounds to produce speciesthat can subsequently be converted to various functionalized POSScompounds.

SUMMARY OF THE INVENTION

Broadly the present invention provides a method for controlling thestereo chemistry of X groups to exo or endo positions on a polyhedraloligomeric silsesquioxane (POSS) compound including, adding reagentsselected from the group of a) CF₃SO₃H then H₂O, b) Me₃SnOH then HCl aq.and c) HBF₄/BF₃ then Me₃SnOH then HCl aq, to the X groups to change oneor more positions thereof to endo or exo, wherein the POSS compound isof the formula [(RSiO_(1.5))_(m)(RXSiO_(1.0))_(n)]_(Σ#), n=4-24, m=1-12,#=m+n, R is aliphatic, aromatic, olefinic, alkoxy, siloxy or H and the Xgroups are selected from the type of OH, OSO₂ CF₃, OSO₂CH₃, F, Cl, I,Br, Me₃SnO, alkoxy and siloxy. Also provided are the POSS species formedby the above inventive method.

The invention further provides a method for inserting a ring substituentinto a polyhedral oligomeric silsesquioxane (POSS) compound to produce aformula of the type [(RSiO 1.5)_(m)(RSiO_(1.0))_(n)(E)_(j)]_(Σ#). Thisincludes, reacting [(RSiO_(1.5))_(m)(RXSiO_(1.0))_(n)]_(Σ#), with areagent selected from the group of H₂NR, RB(OH)₂, K₂CrO₄, R₄NHSO₄ andH₂PR to obtain at least one expanded POSS ring in[(RSiO_(1.5))_(m)(RSiO_(1.0))_(n)(E)_(j)]_(Σ#), where n is 4-24, m is1-12, j is 1-8, # is m+n+j, R is aliphatic, aromatic, olefinic, alkoxy,siloxy or H, X is selected from the group of OSO₂CF₃, OSNMe₃, OH,OSO₂Cl, OSO₂CH₃, OS₃H and halide and E is a ring substituent replacementfor oxygen selected from the group of NR, PR, CrO₄, SO₄, O₂BR, O₂PR andO₂P(O)R. Also provided are the POSS species formed by such inventivemethod.

Definition of Molecular Representations for POSS Nanostructures

For the purposes of explaining this invention's processes and chemicalcompositions the following definition for representations ofnanostructural-cage formulas is made:

Polysilsesquioxanes are materials represented by the formula[RSiO_(1.5)]_(∞) where ∞=degree of polymerization within the materialand R=organic substituent (H, cyclic or linear aliphatic or aromaticgroups that may additionally contain reactive functionalities such asalcohols, esters, amines, ketones, olefins, ethers or halides).Polysilsesquioxanes may be either homoleptic or heteroleptic. Homolepticsystems contain only one type of R group while heteroleptic systemscontain more than one type of R group.

POSS nanostructure compositions are represented by the formula:

[(RSiO_(1.5))_(n)]_(Σ#) for homoleptic compositions

[(RSiO_(1.5))_(m)(RSiO_(1.5))_(n)]_(Σ#) for heteroleptic compositions

[(RSiO_(1.5))_(m)(RXSiO_(1.0))_(n)]_(Σ#) for functionalized heterolepticcompositions

[(RSiO_(1.5))_(m)(RSiO_(1.0))_(n)(E)_(j)]_(Σ#) for heterofunctionalizedheteroleptic compositions

[(XSiO_(1.5))]_(Σ#) for homoleptic silicate compositions

In all of the above R is the same as defined above and X includes OH,Cl, Br, I, alkoxide (OR), acetate (OOCR), peroxide (OOR), amine (NR₂)isocyanate (NCO), and R. The symbol E refers to elements within thecomposition that include (silanes and silicones e.g. SiR₂,SiR₂OSiR₂OSiR₂), (metals and nonmetals e.g. CrO₂, PO₂, SO₂, NR) Thesymbols m, n and j refer to the stoichiometry of the composition. Thesymbol Σ indicates that the composition forms a nanostructure and thesymbol # refers to the number of silicon atoms contained within thenanostructure. The value for # is usually the sum of m+n or m+n+j. Itshould be noted that Σ# is not to be confused as a multiplier fordetermining stoichiometry, as it merely describes the overallnanostructural characteristics of the POSS system (aka cage size).

By “strong acid”, as used herein, is meant one with a pKa number rangingfrom −7 to 5 and is inclusive of superacids which cannot be assigned pKavalues but which are characterized by Hammett acidity values H₀ thatrange from 30 to 2.0 with the preferred range being 8-16.

Thus the present invention discloses methods that enable the selectivemanipulation of the silicon-oxygen frameworks in polyhedral oligomericsilsesquioxane (POSS) cage molecules. It is desired to selectivelymanipulate the frameworks of POSS compounds because they are useful asintermediate chemical agents that can be further converted orincorporated into a wide variety of chemical feed-stocks useful for thepreparation of catalyst supports, monomers, and polymers wherein theyimpart new and improved thermal, mechanical and physical properties tocommon polymeric materials.

Further the present invention teaches processes that enable themanipulation of the silicon-oxygen frameworks (the cage-like structure)of common polyhedral oligomeric silsesquioxane (POSS) compounds[(RSiO_(1.5))_(n)]_(Σ#) (where R=aliphatic, aromatic, olefinic, alkoxy,siloxy or H and n=4-24) into new POSS species bearing frameworks withfunctionalities (e.g. silanes, silylhalides, silanols, silylamines,organohalides, alcohols, alkoxides, amines, cyanates, nitriles, olefins,epoxides, organoacids, esters, and strained olefins) for grafting,polymerization, or catalysis reactions.

Also in contrast to the prior art, the invention provides for thedevelopment of acid catalyzed processes that rapidly and effectivelyopen the silicon-oxygen frameworks of polyhedral oligomericsilsesquioxanes to produce species that can subsequently be convertedinto stable incompletely condensed POSS-silanol and relatedfunctionalized POSS compounds. The use of acid reagents is desirablebecause the silicon-oxygen frameworks in polyhedral oligomericsilsesquioxanes are more tolerant of acids and hence will not as readilypolymerize to form random networks, ladder polymers or other resinoussystems. Acid reagents are also desirable in that their selectivity,rate of action, and the extent of reaction with fully condensedsilicon-oxygen frameworks can be controlled through concentration, acidstrengths (pH), and the chemical nature of the acid and its conjugatebase. The nature of the solvent medium can also impart control over thecage opening process. Manipulation of these process variables allows forthe optimization of conditions by which the silicon-oxygen frameworks ofpolyhedral oligomeric silsesquioxanes such as [(RSiO_(1.5))_(n)]_(Σ#)(where R=aliphatic, aromatic, olefinic, alkoxy or siloxy or H andn=4-24) can be selectively manipulated to produce new polyhedraloligomeric silsesquioxanes with functionalized structures. Thepolyhedral oligomeric silsesquioxanes produced from the acid treatmentprocesses can be used directly as reagents in polymerizations or theycan be additionally derivatized through reaction with a variety oforganosilanes or organic reagents such as amines, phosphines, transitionmetals, or tin complexes to form diverse new POSS chemical reagents.

Thus processes for the selective ring opening, stereochemicalinterconversion, expansion and reduction of the silicon oxygenframeworks in polyhedral oligomeric silsesquioxanes (POSS) to form newpolyhedral oligomeric silsesquioxane chemical species have beendeveloped. The selective ring-opening and stereochemical interconversionprocesses principally utilize strong acids (e.g., HBF₄/BF₃, CF₃SO₃H(trifluoromethanesulfonic acid), ClSO₃H (chlorosulfonic acid), CH₃SO₃H(methanesulfonic acid), H₂S04 (sulfuric acid), HClO₄ (perchloric acid),etc.) to react with the silicon-oxygen-silicon framework's (Si—O—Si)bonds. Conditions in the processes can be controlled so that the Si—O—Siframeworks are selectively cleaved to afford species containing Si—Xbonds where X is the conjugate base of the respective strong acid (e.g.,X=F, CF₃SO₃, ClSO₃, HSO₄, ClO₄) or where X=OH. The resulting newpolyhedral oligomeric silsesquioxane species can then undergo additionalchemical manipulations, such as cage expansion or reduction toultimately be converted into POSS-species bearing one or morefunctionalities suitable for polymerization reactions.

DETAILED DESCRIPTION OF THE INVENTION

Examples of openable POSS systems are shown below.

SECTION A Manipulations of Silicon-oxygen Frameworks in POSS Systems

The invention provides for manipulation of silicon-oxygen frameworks inP0SS Systems. Such processes utilize acid reagents and POSScompounds[(RSiO_(1.5))_(n)]_(Σ#), where R=organic substituent (H. cyclicor linear aliphatic, aromatic, olefinic, alkoxy or siloxy groups thatcan additionally contain reactive functionalities such as alcohols,esters, amines, ketones, olefins and ethers) and where n=an integer from4 to 14 with n=6-12 being preferred. The processes allow for theconversion of low cost, easily produced polyhedral oligomericsilsesquioxanes of the formula [(RSiO_(1.5))_(n)]_(Σ#) to be convertedinto more desirable polyhedral oligomeric silsesquioxanes of the type[(RSiO_(1.5))_(m)(RXSiO_(1.0))_(n)]_(Σ#) where m=1-12, n=4-24 and X=theweak conjugate base of the strong acid including F, OH, SH, NHR or NR2(where R=as defined above), ClO₄, SO₄, SO₃CF₃, SO₃Cl, SO₃CH₃, NO₃, PO₄,Cl or OH. Formulations of the type[(RSiO_(1.5))_(m)(RXSiO_(1.0))_(n)]_(Σ#) can be used as stand-alonechemical reagents or further derivatized into a diverse number of otherPOSS chemical species.

Thus polyhedral oligomeric silsesquioxanes of the type[(RSiO_(1.5))₆]_(Σ6) (Formula 1) are readily converted using the abovementioned acids into formula [(RSiO_(1.5))₄(RXSiO_(1.0))₂]_(Σ6), Formula7 and [(RSiO_(1.5))₂(RXSiO_(1.0))₄]_(Σ6), where Formula 8 and Formula 9are geometrical isomers. Also a twisted cage can be formed per formula7d.

Also polyhedral oligomeric silsesquioxanes of the type[(RSiO_(1.5))₈]_(Σ8) (Formula 2) are readily converted using the abovementioned acids into formula [(RSiO_(1.5))₆(RXSiO_(1.0))₂]_(Σ8), whereFormula 10 and Formula 11 are geometrical isomers.

Thus the present invention also provides processes that promote thestructural rearrangement of silicon-oxygen frameworks, e.g., theconversion of Formula 1 to Formula 7d and of Formula 2 to Formula 11.

It is desirable to rearrange the silicon-oxygen frameworks in POSSsystems in order to change the overall 3-dimensional topology of POSSmolecules and thereby tailor their physical properties. Throughrearranging the silicon-oxygen structural frameworks, improvements inmechanical properties such as tensile, compressive, abrasion resistance,modulus and thermal properties such as glass and melt transitiontemperatures as well as morphological and microstructural control can bebetter achieved in polymer systems which contain POSS.

The structural rearrangement of POSS's silicon-oxygen frameworksinvolves the following sequence: opening of the silicon oxygen ring,rearrangement of the framework, closure of the framework. The processesin this disclosure describe the use of acidic reagents to open POSS'ssilicon-oxygen rings and in some cases these same processes andconditions also promote the rearrangement of the rings. The closure ofthe rings usually involve the net elimination of at least one or moreoxygen atoms from silicon-oxygen framework as compared to the originalformula. For example, the conversion of formula 1 to formula 7d (orformula 2 into formula 11) necessarily involves the elimination of anoxygen atom from the framework. The oxygen atom that has been removedfrom the framework may either be eliminated entirely from the POSSmolecule or it may be relocated external to the framework as a reactivefunctionality such as a silanol.

Polyhedral oligomeric silsesquioxanes of the type[(RSiO_(1.5))_(m)(R³SiO_(1.5))_(n)]_(Σ#) [such as[(RSiO_(1.5))₇(R³SiO_(1.5))₁]_(Σ8), Formula 6], where more than one typeof R is contained within the same molecule and are readily converted,using the above mentioned acids, into a variety of isomers of formula[(RSiO_(1.5))₆(RXSiO_(1.0))₁(R³XSiO_(1.0))₁]_(Σ8), where Formula 12a,Formula 12b, and Formula 12c are all geometrical isomers.

The action of the above mentioned acids and reagents can also becontrolled in such a manner that the silicon atoms can be entirelyremoved from the silicon oxygen frameworks of polyhedral oligomericsilsesquioxanes. The process is especially effective whensilisesquioxanes of the formula [(RSiO_(1.5))_(m)(R³SiO_(1.5))_(n)]_(Σ#)[such as [(RSiO_(1.5))₇(R³SiO_(1.5))₁]_(Σ8)), Formula 6], which containmore than one type of R group, are utilized. In such cases formula ofthe type [(RSiO_(1.5))₄(R³XSiO_(1.0))₃]_(Σ7) can be prepared. Thisrepresents an entirely new synthetic route for the preparation of thevery useful incompletely condensed trisilanol reagents such as[(RSiO_(1.5))₄(R³XSiO_(1.0))₃]_(Σ7) where X=OH in particular. Formulas13a and 13b are stereochemical isomers.

Polyhedral oligomeric silsesquioxanes of the type [(RSiO_(1.5))₁₀]_(Σ10)(Formula 3) and [(RSiO_(1.5))₁₂]_(Σ12) (Formula 4) are also readilyconverted using the above mentioned acids into formula [(RSiO1.5)₈(RXSiO_(1.0))₂]_(Σ10) (Formula 14a) or[(RSiO_(1.5))₁₀(RXSiO_(1.0))₂]_(Σ12) where Formula 15a and Formula 15bare geometrical isomers.

Process Variables Controlling the Manipulation of POSS Frameworks

As is typical with chemical processes there are a number of variablesthat can be used to control the purity, selectivity, rate and mechanismof any process. Variables influencing the process for the cleavage andmanipulation of silicon-oxygen frameworks in polyhedral oligomenicsilsesquioxanes include the following: chemical class of acid,silicon-oxygen ring size, silicon-oxygen ring type[(RSiO_(1.5))_(m)]_(Σ190), (silsesquloxane),[(RSiO_(1.5))_(m)(RSiO_(1.0))_(n)(R₂Si)_(j)]_(Σ#)(silsesquioxane-siloxane),[(RSiO_(1.5))_(m)(RSiO_(1.0))_(n)(ROSi)_(j)]_(Σ#)(silsesquioxane-silicate), (where m=1-12 and n=4-24, j=1-8), effect ofthe organic substituents, process temperature, process solvent, processcatalyst. Each of these variables is briefly discussed below. It is alsoenvisioned that specific catalysts can be developed to promote orenhance the cage-opening action of the acids. Specifically, Lewis acids,including zinc compounds (e.g. ZnBr₂, ZnCl₂ and ZnF₂ as well as SnCl₄,SbCl₅, FeCl₃ and TiCl₄) aluminum compounds (e.g. Al₂H₆, LiAlH₄, AlI₃,AlBr₃, AlCl₃ and AlF₃) boron compounds (e.g. RB(OH)₂, BI₃, BBr₃, BCl₃and BF₃) are known to play important roles in the ring-openingpolymerization of cyclic silicones in the ring-opening of polyhedraloligomeric silsesquioxanes.

Chemical Class of Acids

There are a number of strong acids that can be used to open thesilicon-oxygen framework in POSS compounds. We have found that the acidssuch as HBF₄ operating in the presence of BF₃ are highly effective forcage-opening reactions. This acid is particularly effective forproducing cage-opened products with exo-functionalities such as Formula7-15 The effective ratio of HBF₄/BF₃ ranges from 0.25 to 10 with a ratioof 2.5 being preferred. The concentration of HBF₄/BF₃ can be varied andimpacts both the extent and selectivity of the process. For example adeficiency of HBF₄/BF₃ to POSS is used to produce an POSS-exodifluorideproduct Formula 7 that has been side opened. The use of an excess ofHBF₄/BF₃ to POSS, results in POSS-exotetrafluoride products Formula 8and Formula 9 that have undergone two or more cage openings. Selectivityto produce singly cage-opened products can be carried out using adeficiency of HBF₄/BF₃ to POSS reagent in a 1.0 molar equivalents ofHBF₄ to 3.0 molar equivalents of BF₃ ratio with a ratio of 1.5 beingpreferred. The HBF₄/BF₃ combination is effective at opening thesilicon-oxygen frameworks at 24° C. and 1 atmosphere, however it isrecognized that variations in temperature and pressure can be used toeither enhance or reduce the action of this system. It is alsorecognized that the use of other co-reagents such as BCl₃, boron oxides,aluminum oxides, zinc oxides may be used in place of BF₃ to promote thecage opening process through dehydration or other means.

Alternatively other strong acids and mixtures of strong acids can beutilized to carryout the cage-opening reactions. Classes of these acidsinclude: sulfonic acids (e.g. HSO₃CF₃ triflic acid, HSO₃Clchlorosulfonic acid, HSO₃CH₃ methanesulfonic acid, and toluenesulfonicacids e.g. tosylates), superacids (e.g. HF/SbF₅), mineral acids (e.g.HI, HBr, HCl, H₂SO₄, HNO₃, HClO₄). In some cases the anhydride of theseacids may also be utilized provided that there is a trace amount ofwater present to generate a catalytic amount of the acid from theanhydride. This is particularly the case with triflic anhydride which isthe anhydride of triflic acid. One advantage of using the anhydride overthe acid is that the anhydride may facilitate the reaction by actingboth as an acid source and as a dehydrating agent. This eliminates theneed for co-reagents such as BF₃ mentioned above.

There are additional advantages of using the above listed acids over theHBF₄/BF₃ system in terms of controlling the stereochemistry of thecage-opened product and the extent of reaction. For example triflic acid(and triflic anhydride) is effective at opening POSS compounds to formexo-[(RSiO_(1.5))_(m)(R(F₃CSO₃)SiO_(1.0))_(n)]_(Σ#) complexes that uponundergoing hydrolysis can be used to produce POSS systems with endostereochemistry (e.g. endo-[(RSiO_(1.5))_(m)(R(HO)SiO_(1.0))_(n)]_(Σ#)compounds). When triflic acid or methanesulfonic acids are employed forthe manipulation of the silicon oxygen frameworks in POSS cages, a 2-12fold excess of the acid, relative to the molar equivalence of POSS, issuitable, with a 6 fold excess being preferred.

Silicon-oxygen Ring Size, Ring Type and Cage Sizes

The process discussed in this disclosure is not limited to specificsizes of POSS cages. As shown the process can be carried out on cagescontaining four to fourteen or more silicon atoms making up thesilicon-oxygen framework. It has been noted that the silicon-oxygen ringsize contained within such POSS systems does affect the rate at whichcage opening can occur. For example rings containing three silicon atomsand three oxygen atoms as in Formula 1, appear to open faster than thelarger rings containing 4 silicons and 4 oxygens (Formula 2). Therelative rate for the opening of POSS silicon-oxygen rings appears to besix membered rings with three silicons>eight membered rings with foursilicons>ten membered rings with five silicons>twelve membered ringswith six silicons. Knowledge of this information allows the user of thisprocess to control which silicon-oxygen rings within a POSS moleculewill be opened. For example Formula 1 contains two six-membered ringsand three eight membered silicon oxygen rings yet because the sixmembered rings within the molecule open at a faster rate than the eightmembered rings, the molecule can be selectively functionalized at sitesalong the six membered ring to form Formula 7 and Formula 8.

Effect of the Organic Substituent, Process Solvents and ProcessTemperatures

The process described in this disclosure is not limited to POSS systemsbearing specific organic groups (defined as R) attached to the siliconatom of the silicon-oxygen ring systems. The processes are amenable toopening the POSS systems bearing a wide variety of organic groups. Theorganic substituent does have a large effect on the solubility of boththe final product and the starting POSS material. Therefore it isenvisioned that the different solubilities between the starting POSScompounds and their respective cage-opened products can be used tofacilitate the separation of and purification of the final reactionproducts. The process has been carried out in a wide range of solventssuch as CCl₄, CHCl₃, CH₂Cl₂, fluorinated solvents, aromatics(halogenated and nonhalogenated), aliphatic (halogenated andnonhalogenated). The variables of solvent type, POSS concentration, andprocess temperature should be utilized in the standard way to match thespecific cage opening process to the equipment available

Table of Selected POSS Feedstocks and their Cage-opened Products. AcidYield Starting POSS Reagents (%) New POSS System[(c-C₆H₁₁SiO_(1.5))n]_(Σ6) HBF₄/BF₃ 13.6[(c-C₆H₁₁SiO_(1.5))₂(c-C₆H₁₁(F)SiO_(1.0))₄]_(Σ6) (Formula 8, X = F) 0.2[(c-C₆H₁₁SiO_(1.5))₂(c-C₆H₁₁(F)SiO_(1.0))₄]_(Σ6) (Formula 9, X = F) 68[(c-C₆H₁₁SiO_(1.5))₄(c-C₆H₁₁(F)SiO_(1.0))₂]_(Σ6) (Formula 7a, X = F)10.2 [(c-C₆H₁₁SiO_(1.5))₂(c-C₆H₁₁(F)SiO_(1.0))₁(c-C₆H₁₁(HO)SiO_(1.0))₁]_(Σ6) (Formula 7c, X = OH, F)[(c-C₆H₁₁SiO_(1.5))₆]_(Σ6) HBF₄/BF₃ 92[(c-C₆H₁₁SiO_(1.5))₂(c-C₆H₁₁(F)SiO_(1.0))₄]_(Σ6) (Formula 8, X = F) 8[(c-C₆H₁₁SiO_(1.5))₂(c-C₆H₁₁(F)SiO_(1.0))₄]_(Σ6) (Formula 9, X = F)[(c-C₆H₁₁SiO_(1.5))₆]_(Σ6) MsOH 70[(c-C₆H₁₁SiO_(1.5))₄(c-C₆H₁₁(MS)SiO_(1.0))₂]_(Σ6) (Formula 7d, X = OMs)[(H₂C═CHSiO_(1.5))₈]_(Σ8) HBF₄/BF₃ 37[(H₂C═CHSiO_(1.5))₆(H₂C═CH(F)SiO_(1.0))₂]_(Σ8) (Formula 10, X = F)[(C₂H₅SiO_(1.5))₈]_(Σ8) HBF₄/BF₃ 80[(C₂H₅SiO_(1.5))₆(C₂H₅(F)SiO_(1.0))₂]_(Σ8) (Formula 10, X = F)[(C₂H₅SiO_(1.5))₈]_(Σ8) H₂SO₄/SO₃ 7[(C₂H₅SiO_(1.5))₆(C₂H₅(HO₃SO)SiO_(1.0))₂]_(Σ8) (Formula 10, X = OSO₃H)21 [(C₂H₅SiO_(1.5))₆(C₂H₅(HO₃SO)SiO_(1.0))₂]_(Σ8) (Formula 11, X =OSO₃H) [(C₂H₅SiO_(1.5))₈]_(Σ8) ClSO₃H 31[(C₂H₅SiO_(1.5))₆(C₂H₅(ClO₂SO)SiO_(1.0))₂]_(Σ8) (Formula 10, X = OSO₂Cl)[(c-C₆H₁₁SiO_(1.5))₈]_(Σ8) HBF₄/BF₃ 85[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁(F)SiO_(1.0))₂]_(Σ8) (Formula 10, X = F)[(c-C₆H₁₁SiO_(1.5))₈]_(Σ8) TfOH 100[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁(TfO)SiO_(1.0))₂]_(Σ8) (Formula 10, X = OTf)[(c-C₆H₁₁SiO_(1.5))₈]_(Σ8) Tf₂O 100[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁(TfO)SiO_(1.0))₂]_(Σ8) (Formula 10, X = OTf)[(c-C₆H₁₁SiO_(1.5))₈]_(Σ8) TfOH 70[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁(TfO)SiO_(1.0))₂]_(Σ8) (Formula 11, X = OTf)[(p- HBF₄/BF₃ 80 [(p-CH₃C₆H₄SiO_(1.5))₆(p- CH₃C₆H₄SiO_(1.5))₈]_(Σ8)CH₃C₆H₄(F)SiO_(1.0))₂]_(Σ8) (Formula 10, X = F) [(c- HBF₄/BF₃ 66[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁ C₆H₁₁SiO_(1.5))₇(F)SiO_(1.0))₁(C₆H₅CH₂(F)SiO_(1.0))₁]_(Σ8) (Formula(C₆H₅CH₂SiO_(1.5))₁]_(Σ8) 10, X = F) [(c- HBF₄/BF₃ 33[(c-C₅H₉SiO_(1.5))₆(c-C₅H₉(F)SiO_(1.0))₁(CH₃C₅H₉SiO_(1.5))₇(CH₃SiO_(1.5))₁]_(Σ8) (F)SiO_(1.0))₁]_(Σ8) (Formula 10, X= F) [(CH₃SiO_(1.5))₁₀]_(Σ10) HBF₄/BF₃ 24[(CH₃SiO_(1.5))₈(CH₃(F)SiO_(1.0))₂]_(Σ10) (Formula 14, X = F)[(c-C₆H₁₁SiO_(1.5))₁₂]_(Σ12) HBF₄/BF₃ 70[(c-C₆H₁₁SiO_(1.5))₁₀(c-C₆H₁₁(F)SiO_(1.0))₂]_(Σ12) (Formulas 15a and15b, X = F) [(c-C₆H₁₁SiO_(1.5))₈(c-C₆H₁₁(F)SiO_(1.0))₄]_(Σ12) (a) TfOH =CF₃SO₃H; MsOH = CH₃SO₃H; H₂SO₄/SO₃ = 20% fuming sulfuric acid

SECTION B Isomers of POSS Systems

Given the three dimensional and nanoscopic nature of POSS systems it isimportant to realize that a number of isomeric forms for any givenformula can be produced by the methods of the invention. Thestereochemistry of these isomers can be controlled by the inventivemethods taught herein, however, in some cases geometrical isomers willstill exist. A number of examples are provided to convey the presence ofsuch isomers and that the invention is not limited to thosestereochemical or geometrical isomers shown herein.

Examples of six isomers for difunctional incompletely condensed[(RSiO_(1.5))₄(RXSiO_(1.0))₂]_(Σ6) systems are:

Note that Formula 7 differs from formula 16 in that the silicon-oxygenframework of formula 7 has been cleaved along one of its six memberedrings while formula 16 has been cleaved along one of its eight memberedrings.

Examples of eight isomers for tetrafunctional twisted[(RSiO_(1.5))₂(RSiO_(1.0))₄]_(Σ6) systems are:

Examples of six isomers for tetrafunctional incompletely condensed[(RSiO_(1.5))₂(RXSiO_(1.0))₄]_(Σ6) systems are:

Examples of three isomers for difunctional twisted[(RSiO_(1.5))₆(RXSiO_(1.0))₂]_(Σ8) systems are:

Examples of twelve isomers for difunctional[(RSiO_(1.5))₆(R³XSiO_(1.0))₁(RXSiO_(1.0))₁]_(Σ8) systems are:

SECTION C Methods for Controlling Stereochemistry

The processes described above enable the manipulation of thesilicon-oxygen frameworks within any POSS molecular structure. Howeverit is advantageous to control the stereochemistry of the reactivefunctionalities now located on these molecules. Four general processeshave now been identified to accomplish any type of stereochemicalmanipulation that is so desired. It is important to note that POSSmolecules are three-dimensional nanostructured molecular systems andbecause of this the primary stereochemical considerations are whetherthe functionality in question is oriented externally or internally withrespect to the center of a particular face (or side) of the cage. If afunctionality is projected externally (away from) the center face of thecage it is referred to as having exo-stereochemistry whilefunctionalities projecting toward the center of any face are referred toas having endo stereochemistry. Depending on the type of manipulation ordesired use for the cage, it is of high value to the materialmanufacturer (chemist) to control the stereochemical nature of suchproducts. Again these techniques can be used to control thestereochemistry of X functionalities on any size of POSS cage.

Method 1

Process for the Inversion of Stereochemistry

This method involves the hydrolysis of the X group on formulas 7, 10 toa silanol species of formulas 7, 10 with inversion of stereochemistry.The method is particularly useful for all X groups excluding fluoride.The method can also be utilized to alter the stereochemistry of silanolfunctionalized versions of formula 7, 10 and simply involves treatmentof the silanol with HBF₄ to form the intermediate species containing theconjugate base of the acid. Treatment of this species with acidic waterreproduces the silanol species with inverted stereochemistry. Theprocess can be used to convert both endo and exo stereochemicalorientation of groups. The process is applicable to any size of POSScage where n=4 to 14 in [(RSiO_(1.5))_(n)]_(Σ#).

Method 1 can be used to alter the stereochemistry of X groups on allsizes of polyhedral oligomeric silsesquioxane cages. The example belowshows that the process can be carried out on POSS systems bearing sixsilicon atoms within the framework.

In some instances it is possible to carry out the conversion process soformula-bearing mixed stereochemical (endo-exo) functionalities areformed.

Method 2

A Two Step Process for the Retention of Stereochemistry.

This method is particularly useful for formula bearing X groupsespecially where X=F. The process involves the treatment of[(RSiO_(1.5))_(m)(RFSiO_(1.0))_(n)]_(Σ#) first withtrimethyltinhydroxide to form the species[(RSiO_(1.5))_(m)(R(Me₃SnOSiO_(1.0))_(n)]_(Σ#) followed by treatment ina second step with concentrated hydrochloric acid (or HCl aq., such as1-12N and preferably 2-4N HCl) to produce a silanol species[(RSiO_(1.5))_(m)(R(HO)SiO_(1.0))_(n)]_(Σ#) in which the silanol groupsoccupy the same stereochemical position relative to the F groups in thestarting compound. The process is applicable to any size of POSS cagewhere n=4 to 14 in [(RSiO_(1.5))_(n)]_(Σ#).

Reactions of Formula 7a or 10a with Grignard reagents (RMgX) or hydridereducing agents (such as LiAlH₄ and Al₂H₆) also proceed with inversionof stereochemistry to produce the corresponding di-exo species ofFormulas 7a and 10a.

Method 2 can be used to alter the stereochemistry of X groups on allsizes of polyhedral oligomeric silsesquioxane cages. The example belowshows that the process can be carried out on POSS systems bearing sixsilicon atoms within the framework.

Reactions of Formula 7a or 10a with alkyllithium reagents (e.g., CH₃Li,C₆H₅CCLi and CH₂═CHLi) also proceed with retention of stereochemistry toproduce the corresponding di-exo species of Formulas 7a and 10a.

Method 3

A Three Step Process for Inversion of Stereochemistry

A variation of the Method 2 process can be utilized to invert thestereochemistry of silanol groups. The method provides treatment of thesilanol species [(RSiO_(1.5))_(m)(R(HO)SiO_(1.0))_(n)]_(Σ#) withHBF₄/BF₃ to produce the [(RSiO_(1.5))_(m)(R(F)SiO_(1.0))_(n)]_(Σ#)species followed by subsequent treatment with Me₃SnOH and concentratedHCl as described above. The process is applicable to any size of POSScage where n=4 to 14 in [(RSiO_(1.5))_(n)]_(Σ#).

Method 3 can be used to invert the stereochemistry of X groups on allsizes of polyhedral oligomeric silsesquioxane cages. The example belowshows that the process can be carried out on POSS systems bearing sixsilicon atoms within the framework.

Method 4

Combination of the Above Methods for Full Manipulation of X Groups andStereochemistry.

The methods described for controlling the stereochemistry in thesesystems can also be effectively used in tandem to both vary the chemicalnature of the X group in [(RSiO_(1.5))_(m)(RXSiO_(1.0))_(n)]_(Σ#)systems as well as to interconvert the stereochemical nature of the Xgroups. Therefore any and all stereochemical isomers for the formulasdescribed in this work are accessible and to be claimed.

SECTION D POSS Cage Expansions and New Reagent Synthesis

This section shows that the incompletely condensed POSS-silanols arevery valuable reagents as they can be used to produce even more diversePOSS feedstocks. Examples are listed for expansion of formula 7, 8, 10.Note that in such processes formula bearing silanol groups withendo-stereochemistry are particularly useful for reacting with Y₂SiR¹R²silane reagents where R¹ and R² are the same or different from the grouppreviously defined for R (e.g. R¹=H, methyl, ethyl, vinyl, allyl andphenyl) while Y=halides (e.g. Cl, Br, I) or amines such as NR₂ (e.g.dimethylamine N(CH₃)₂, N(CH₂CH₃)₂, etc.). The process of reactingformula 7 or formula 8 with either one or two equivalents of Y₂SiR¹R²silane reagents results in a net expansion of the number of siliconatoms contained within the silicon oxygen framework of the originalformula. In this manner the silicon-oxygen framework structures can beselectively enlarged as well as functionalized. This process isimportant because Formula 5 has undergone a formal expansion of thenumber of silicon atoms contained within its ring systems. Such anexpansion is unprecedented and the rings now contain both (RSiO_(1.5))and (R₂SiO) types of silicon atoms. Furthermore, functionalities usefulfor polymerizations and grafting can be incorporated into the moleculethrough the two organic R-groups located on the R₂SiO silicon atom.

This process can be used to expand the silicon-oxygen frameworks for allsizes of polyhedral oligomeric silsesquioxane cages. The example belowshows that the process can be carried out on POSS systems bearing eightsilicon atoms within the framework.

SECTION E Cage Substitutents Other Than Si

The silicon-oxygen frameworks of compounds such as formula 10 can alsobe selectively expanded by atoms other than silicon. For examples Sn, S,N, P, B, and metals such as Cr, Ti, Zr, Ru, Mo, W, Pt, Pd, Al, Ga andFe, can readily be incorporated into the silicon oxygen frameworks asindicated below.

SECTION F Reactivity and Utility of Cage-expanded POSS Formula

This shows that these cage-expanded compounds (formulas 19-21) can beutilized as chemical reagents to regenerate silanols or they can be useddirectly as reagents in grafting or polymerizations or as ligands. Notethat in the case of using these reagents for the production of silanols,additional stereochemical control can be obtained with respect towhether endo or exo stereochemistry will result. For example treatmentof Formula 19 or Formula 20 with concentrated hydrochloric acid producestwo different stereochemical isomers of the same compound.

The following examples serve to illustrate the methods of the presentinvention and should not be construed in limitation thereof.

In such examples: CHCl₃ and CDCl₃ were distilled over CaH₂ prior to use.All other solvents were used as purchased without purification.HBF₄.OMe₂ was purchased commercially and used without furtherpurification. BF₃.OEt₂ was prepared by bubbling BF₃ into a solution ofdry OEt₂, and then distilled under reduced pressure. Me₃SnOH wasprepared by reacting an ether solution of Me₃SnCl with aqueous sodiumhydroxide; the white precipitate was filtered and dried in vacuum (0.001Torr, 23° C.) prior to use. Trifluoromethanesulfonic, methanesulfonicand chlorosulfonic acids were distilled over P₂O₅.Trifluoromethanesulfonic anhydride was prepared by stirringtrifluoromethanesulfonic acid over P₂O₅ and was distilled under reducedpressure. Methyl 3,3-dimethyl-4-pentenoate was distilled over CaH₂.

Manipulation of POSS Silicon-oxygen Frameworks EXAMPLE 1 Preparation ofexo-[(c-C₆H₁₁SiO_(1.5))₄(c-C₆H₁₁(F)SiO_(1.0))₂]_(Σ) ₆ (Formula 7)

To a solution of [(c-C₆H₁₁SiO_(1.5))₆]_(Σ6) (Formula 1) (2.038 g, 2.51mmol) in 15 mL of CHCl₃ was added a mixture of HBF₄.OMe₂ (0.460 mL, 3.77mmol) and BF₃.OEt₂ (0.720 mL, 5.65 mmol). After 10 h at roomtemperature, the volume was reduced to ˜5 mL in vacuo and 5 mL of CH₃CNwas added. Formation of two phases was noted. The solution was reducedagain to ˜3 mL. The white precipitate was collected by filtration andrinsed with copious amount of CH₃CN. A second washing with CH₃CN wasdone by dissolving the crude product mixture in CH₃Cl andreprecipitating with CH₃CN as described above. Spectroscopic analysis(¹H, ¹³C, ²⁹Si NMR) at this point indicated the presence of unreacted[(c-C₆H₁₁SiO_(1.5))₆]_(Σ6) (Formula 1) (8.1%),exo-[(c-C₆H₁₁SiO_(1.5))₂(c-C₆H₁₁(F)SiO_(1.0))₄]_(Σ6) (Formula 8) (13.6%)exo-[(c-C₆H₁₁SiO_(1.5))₂(c-C₆H₁₁(F)SiO_(1.0))₄]_(Σ6) (Formula 9) (0.2%),exo-[(c-C₆H₁₁SiO_(1.5))₄(c-C₆H₁₁(F)SiO_(1.0))₂]_(Σ6) (Formula 7) (67.9%)andexo-endo-[(c-C₆H₁₁SiO_(1.5))₄(c-C₆H₁₁(F)SiO_(1.0))₁(c-C₆H₁₁(HO)SiO_(1.0))₁]_(Σ6)(Formula 7) (10.2%). Slow evaporation of a CH₃Cl/CH₃CN solution of thecrude product afforded 735 mg of (13:87) mixture of[(c-C₆H₁₁SiO_(1.5))₆]_(Σ6) (Formula 1) andexo-[(c-C₆H₁₁SiO_(1.5))₄(c-C₆H₁₁(F)SiO_(1.0))₂]_(Σ6) (Formula 7).

EXAMPLE 2 Preparation ofexo-[(c-C₆H₁₁SiO_(1.5))₂(c-C₆H₁₁(F)SiO_(1.0))₄]_(Σ6) (Formula 8)

The reaction was performed as described as in Example 1 using[(c-C₆H₁₁SiO_(1.5))₆]_(Σ6) (Formula 1) (1.005 g, 1.24 mmol), HBF₄.OMe₂(1.2 mL, 9.86 mmol) and BF₃.OEt₂ (1.9 mL, 14.99 mmol) in 15 mL of CHCl₃(room temp, 3.5 h). Spectroscopic analysis (¹H, ¹³C, ²⁹Si NMR) of thecrude reaction product indicated the presence ofexo-[(c-C₆H₁₁SiO_(1.5))₂(c-C₆H₁₁(F)SiO_(1.0))₄]_(Σ6) (Formula 8) (92%)and exo-[(c-C₆H₁₁SiO_(1.5))₂(c-C₆H₁₁(F)SiO_(1.0))₄]_(Σ6) (Formula 9)(8%). Pure exo-[(c-C₆H₁₁SiO_(1.5))₂(c-C₆H₁₁(F)SiO_(1.0))₄]_(Σ6) (Formula8) was obtained by crystallization in acetone at 5° C. Yield: 515 mg(48%). exo-[(c-C₆H₁₁SiO_(1.5))₂(c-C₆H₁₁(F)SiO_(1.0))₄]_(Σ6) (Formula 8.

EXAMPLE 3 Preparation ofexo-[(c-C₆H₁₁SiO_(1.5))₂(c-C₆H₁₁(F)SiO_(1.0))₄]_(Σ6) (Formula 9)

The reaction was performed as described as in Example 1 to prepareexo-[(c-C₆H₁₁SiO_(1.5))₂(c-C₆H₁₁(F)SiO_(1.0))₄]_(Σ6) (Formula 9):¹³C{¹H} NMR (125 MHz, CDCl₃, 25° C.).

EXAMPLE 4 Preparation ofexo-endo-[(c-C₆H₁₁SiO_(1.5))₄(c-C₆H₁₁(F)SiO_(1.0))₁(c-C₆H₁₁(HO)SiO_(1.0))₁]_(Σ6)(Formula 7)

The reaction was performed as described as in Example 1 to prepareexo-endo-[(c-C₆H₁₁SiO_(1.5))₄(c-C₆H₁₁(F)SiO_(1.0))₁(c-C₆H₁₁(HO)SiO_(1.0))₁]_(Σ6)(Formula 7).

EXAMPLE 5 Preparation ofexo-[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁(F)SiO_(1.0))₂]_(Σ8) (Formula 10)

(a) To a solution of [(c-C₆H₁₁SiO_(1.5))₈]_(Σ8) (Formula 2) (60.0 mg,0.055 mmol) in 0.5 mL of CDCl₃ was added a mixture of HBF₄.OMe₂ (33.7mg, 0.253 mmol) and BF₃.OEt₂ (55.2 mg, 0.389 mmol). After 3.5 h at roomtemperature, spectroscopic analysis (¹H, ¹³C, ²⁹Si NMR) indicated thepresence of exo-[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁(F)SiO_(1.0))₂]_(Σ8)(Formula 10) (44%) and unreacted [(c-C₆H₁₁SiO_(1.5))₈]_(Σ8) (Formula 2)(56%). The ratio of exo-[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁(F)SiO_(1.0))₂]_(Σ8)(Formula 10) to [(c-C₆H₁₁SiO_(1.5))₈]_(Σ8) (Formula 2) increased to(85:15) after refluxing for 1.5 h, but was unchanged by further heating.

(b) To a solution of [(c-C₆H₁₁SiO_(1.5))₈]_(Σ8) (Formula 2) (1.172 g,1.083 mmol) in CH₃Cl (12 mL) was added a mixture of HBF₄.OMe₂ (0.730 g,5.453 mmol) and BF₃.OEt2 (1.230 g, 8.666 mmol). The mixture was heatedat 30° C. for 2 h then the solvent was removed under reduced pressure (1Torr). The residue was washed with excess CH₃CN and dried in vacuo (25°C., 1 Torr) to afford 1.048 g of white solid. Spectroscopic analysis(¹H, ¹³C, ²⁹si NMR) at this point indicated the presence of unreacted[(c-C₆H₁₁SiO_(1.5))₈]_(Σ8) (Formula 2) (57%) andexo-[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁(F)SiO_(1.0))₂]_(Σ8) (Formula 10) (43%).Pure exo-[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁(F)SiO_(1.0))₂]_(Σ8) (Formula 10)was isolated via adsorption chromatography (SiO₂, hexanes, R_(f)=0.51).

EXAMPLE 6 Preparation ofexo-[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁(F₃CO₂SO)SiO_(1.0))₂]_(Σ8) (Formula 10a)

To a solution of [(c-C₆H₁₁SiO_(1.5))₈]_(Σ8) (Formula 2) (1.151 g 1.064mol) in benzene (12 mL) was added triflic acid (0.977 mg, 6.510 mmol) atroom temperature. After 45 min., the organic layer was decanted from thetriflic acid layer, mixed with hexane (40 mL), and then cooled to ˜30°C. for 1 h. The organic layer was again decanted from any residualtriflic acid and evaporated (25° C., 1 Torr) to affordexo-[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁(F₃CO₂SO)SiO_(1.0))₂]_(Σ8) (Formula 10)as a pale white, very water-sensitive solid. The yield was quantitative.

EXAMPLE 7 Alternate Preparation ofexo-[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁(F₃CO₂SO)SiO_(1.0))₂]_(Σ8) (Formula 10a)

Exo-[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁(F₃CO₂SO)SiO_(1.0))₂]_(Σ8) (Formula 10a)was prepared by reacting [(c-C₆H₁₁SiO_(1.5))₈]_(Σ8) (Formula 2) andtriflic anhydride in CDCl₃ at 25° C. for 30 min according to theprocedure described above for the synthesis ofexo-[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁(F₃CO₂SO)SiO_(1.0))₂]_(Σ8) (Formula10a).

EXAMPLE 8 Preparation ofexo-twisted-[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁(F₃CO₂SO)SiO_(1.0))₂]_(Σ8)(Formula 11a)

Exo-twisted-[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁(F₃CO₂SO)SiO_(1.0))₂]_(Σ8)(Formula 11a) was prepared in 70% yield by reacting[(c-C₆H₁₁SiO_(1.5))₈]_(Σ8) (Formula 2) (102 mg, 0.094 mmol) and TfOH (83μl, 0.943 mmol) at 25° C. for 3 h according to the procedure describedabove for the synthesis ofexo-[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁(F₃CO₂SO)SiO_(1.0))₂]_(Σ8) (Formula10a).

EXAMPLE 9 Preparation ofexo-[(c-C₆H₁₁SiO_(1.5))₂(c-C₆H₁₁(H₃CO₂SO)SiO_(1.0))₄]_(Σ6) (Formula 8)

Exo-[(c-C₆H₁₁SiO_(1.5))₂(c-C₆H₁₁(H₃CO₂SO)SiO_(1.0))₄]_(Σ6) (Formula 8)was prepared in 70% yield by reacting [(c-C₆H₁₁SiO_(1.5))₆]_(Σ6)(Formula 1) (55.1 mg, 0.068 mmol) and CH₃SO₃H (32.7mg, 0.340 mmol) at60° C. for 8 h according to the procedure described above for thesynthesis of exo-[(c-C₆H₁₁SiO_(1.5))₄(c-C₆H₁₁(F₃CO₂SO)SiO_(1.0))₂]_(Σ6)(Formula 8).

EXAMPLE 10 Preparation ofexo-[(C₂H₅SiO_(1.5))₆(C₂H₅(ClO₂SO)SiO_(1.0))₂]_(Σ8) (Formula 10a)

Exo-[(C₂H₅SiO_(1.5))₆(C₂H₅(ClO₂SO)SiO_(1.0))₂]_(Σ8) (Formula 10a) wasprepared in 31% yield by reacting [(C₂H₅SiO_(1.5))₈]_(Σ8) (Formula 2)(72.4 mg, 0.112 mmol), ClO₃H (11.0 mg, 0.094 mmol) at 25° C. for 15 minaccording to the procedure described above for the synthesis ofexo-[(C₂H₅SiO_(1.5))₆(C₂H₅(ClO₂SO)SiO_(1.0))₂]_(Σ8) (Formula 10a).

EXAMPLE 11 Preparation ofexo-[(CH₂═CHSiO_(1.5))₆(CH₂═CH)(F)SiO_(1.0))₂]_(Σ8) (Formula 10a)

Exo-[(CH₂═CH)₈Si₈O₁₁F₂] (Formula 10a) was prepared in 37% by reacting[(CH₂═CHSiO_(1.5))₈]_(Σ8) (66.7 mg, 0.105 mmol), HBF₄.OMe₂ (39.7 mg,0.297 mmol) and BF₃.OEt₂ (25.4 mg, 0.179 mmol) at 25° C. for 1 haccording to the procedure described above for the synthesis ofexo-[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁)(F)SiO_(1.0))₂]_(Σ8) (Formula 10a).

EXAMPLE 12 Preparation ofexo-[(C₂H₅SiO_(1.5))₆(C₂H₅)(F)SiO_(1.0))₂]_(Σ8) (Formula 10a)

EXo-[(C₂H₅SiO_(1.5))₆(C₂H₅)(F)SiO_(1.0))₂]_(Σ8) (Formula 10a) wasprepared in 80% by reacting [(C₂H₅SiO_(1.5))₈]_(Σ8) (Formula 2) (47 mg,0.072 mmol), HBF₄.OMe₂ (41 mg, 0.308 mmol) and BF₃.OEt₂ (63 mg, 0.444mmol) at 25° C. for 1 h according to the procedure described above forthe synthesis of exo-[(C₂H₅SiO_(1.5))₆(C₂H₅)(F)SiO_(1.0))₂]_(Σ8)(Formula 10a).

EXAMPLE 13 Preparation ofexo-[(p-CH₃C₆H₄SiO_(1.5))₆(p-CH₃C₆H₄)(F)SiO_(1.0))₂]_(Σ8) (Formula 10a)

Exo-[(p-CH₃C₆H₄SiO_(1.5))₆(p-CH₃C₆H₄)(F)SiO_(1.0))₂]_(Σ8) (Formula 10a)was prepared in 80% by reacting exo-[(p-CH₃C₆H₄SiO_(1.5))₈]_(Σ8)(Formula 2) (80.6 mg, 0.070 mmol), HBF₄.OMe₂ (43.1 mg, 0.322 mmol) andBF₃.OEt₂ (61.6 mg, 0.434 mmol) at 25° C. for 3 h according to theprocedure described above for the synthesis ofexo-[(p-CH₃C₆H₄SiO_(1.5))₆(p-CH₃C₆H₄)(F)SiO_(1.0))₂]_(Σ8) (Formula 10a).

EXAMPLE 14 Preparation of exo-[(CH₃SiO_(1.5))₈(CH₃)(F)SiO_(1.0))₂]_(Σ10)(Formula 14)

Exo-[(CH₃SiO_(1.5))₈(CH₃)(F)SiO_(1.0))₂]_(Σ10) (Formula 14) was preparedin 24% yield by reacting [(CH₃SiO_(1.5))₁₀]_(Σ10) (Formula 3) (31.2 mg,0.046 mmol), HBF₄.OMe₂ (12.4 mg, 0.093 mmol) and BF₃.OEt₂ (23.5 mg,0.166 mmol) at 25° C. for 40 min according to the procedure describedabove for the synthesis ofexo-[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁)(F)SiO_(1.0))₂]_(Σ8) (Formula 10a).

EXAMPLE 15 Preparation ofexo-[(c-C₆H₁₁SiO_(1.5))₁₀(c-C₆H₁₁)(F)SiO_(1.0))₂]_(Σ12) (Formulas 15aand 15b)

Exo-[(c-C₆H₁₁SiO_(1.5))₁₀(c-C₆H₁₁)(F)SiO_(1.0))₂]_(Σ12) (Formula 15) wasprepared in 70% overall yield by reactingxo-[(c-C₆H₁₁SiO_(1.5))₁₂]_(Σ12) (Formula 4) (53.0 mg, 0.033 mmol),HBF₄.OMe₂ (26.0 mg, 0.194 mmol) and BF₃.OEt₂ (38.5 mg, 0.271 mmol) at60° C. for 2 h according to the procedure described above for thesynthesis of exo-[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁)(F)SiO_(1.0))₂]_(Σ8)(Formula 10a).

EXAMPLE 16 Preparation ofexo-[(c-C₆H₁₁SiO_(1.5))₆(C₆H₅CH₂)(F)SiO_(1.0))₁(C₆H₅CH₂)(F)SiO_(1.0))₁]_(Σ8)(Formula 11)

A mixture of isomers ofexo-[(c-C₆H₁₁SiO_(1.5))₆(C₆H₅CH₂)(F)SiO_(1.0))₁(C₆H₅CH₂)(F)SiO_(1.0))₁]_(Σ8)(Formula 11) was prepared in 66% yield by reacting[(c-C₆H₁₁SiO_(1.5))₆(C₆H₅CH₂)SiO_(1.5))₁]_(Σ8) (Formula 6) (60.8 mg,0.056 mmol), HBF₄.OMe₂ (32.2 mg, 0.241 mmol) and BF₃.OEt₂ at 60° C. for15 h according to the procedure described above for the synthesis ofexo-[(c-C₆H₁₁SiO_(1.5))₆(C₆H₅CH₂)(F)SiO_(1.0))₁(C₆H₅CH₂)(F)SiO_(1.0))₁]_(Σ8)(Formula 11).

EXAMPLE 17 Preparation ofExo-[(c-C₅H₉SiO_(1.5))₆(C₅H₉)(F)SiO_(1.0))₁(CH₃)(F)SiO_(1.0))₁]_(Σ8)(Formula 12a)

Isomer A ofExo-[(c-C₅H₉SiO_(1.5))₆(C₅H₉)(F)SiO_(1.0))₁(CH₃)(F)SiO_(1.0))₁]_(Σ8)(Formula 12a) was prepared in 33% yield by reacting[(c-C₅H₉SiO_(1.5))₇(CH₃)SiO_(1.5))₁]_(Σ8) (Formula 6) (68.4 mg, 0.075mmol), HBF₄.OMe₂ (20.3 mg, 0.152 mmol) and BF₃.OEt₂ (50.3 mg, 0.354mmol) at 25° C. for 2 h according to the procedure described above forthe synthesis ofexo-[(c-C₅H₉SiO_(1.5))₆(C₅H₉)(F)SiO_(1.0))₁(CH₃)(F)SiO_(1.0))₁]_(Σ8)(Formula 10a).

EXAMPLE 18 Preparation ofendo-twisted-[(c-C₆H11SiO_(1.5))₆((c-C₆H₁₁)(HO)SiO_(1.0))₂]_(Σ8)(Formula 11b)

Endo-twisted-[(c-C₆H₁₁SiO_(1.5))₆((c-C₆H₁₁)(HO)SiO_(1.0))₂]_(Σ8)(Formula 11b) was prepared in 70% yield by hydrolyzingexo-twisted-[(c-C₆H11SiO_(1.5))₆((c-C₆H₁₁)(HO)SiO_(1.0))₂]_(Σ8) (Formula11a) according to the procedure described above for the synthesis ofendo-[(c-C₆H₁₁SiO_(1.5))₆((c-C₆H₁₁)(HO)SiO_(1.0))₂]_(Σ8) (Formula 10a).The product was identical to a sample ofendo-twisted-[(c-C₆H₁₁SiO_(1.5))₆((c-C₆H₁₁)(HO)SiO_(1.0))₂]_(Σ8)(Formula 11b) prepared fromexo-twisted-[(c-C₆H₁₁SiO_(1.5))₆((c-C₆H₁₁)(HO)SiO_(1.0))₂]_(Σ8) (Formula11a) via sequential reactions with HBF₄/BF₃, Me₃SnOH and 6N HCl (i.e.,the established three-step procedure for inverting stereochem of Si—OHgroups).

EXAMPLE 18.5 Preparation of[(c-C₆H₁₁SiO_(1.5))₄((c-C₆H₁₁)(HO)SiO_(1.0))₂]_(Σ6) (Formula 7d)

A solution of CH₃SO₃H (2.33 g, 24.3 mmol) in CHCl₃ was added to asolution of [(c-C₆H₁₁SiO_(1.5))₆]_(Σ6) (Formula 1) (3.90 g, 4.80 mmol)in CHCl₃. The reaction mixture was heated for 4 h at 70° C. withstirring. Evaporation of the solvent (0.1 Torr, 25° C.) afforded a whitemicrocrystalline solid (4.22 g, 89% crude yield). A 1.511 g sample ofthe crude product was stirred in pyridine (˜6 mL) for 10 minutes andfiltered to remove any unreacted [(c-C₆H₁₁SiO_(1.5))₆]_(Σ6) (Formula 1).[(c-C₆H₁₁SiO_(1.5))₄((c-C₆H₁₁)(HO)SiO_(1.0))₂]Σ6 (Formula 7d)precipitated from the filtrate upon addition of CH₃CN (40 mL) to afforda white powder, which was dissolved in Et₂O and washed with 6N HCl.Drying over MgSO₄ and evaporation of the solvent (2 mL) afforded a whitesolid, which was recrystallized from CCl₄ to afford the product ascolorless crystals (584 mg, 39%).

EXAMPLE 19 Preparation ofExo-twisted-[(C₂H₅SiO_(1.5))₆((C₂H₅)(HO₃SO)SiO_(1.0))₂]_(Σ) ₈ (Formula11a) and Exo-[(C₂H₅SiO_(1.5))₆((C₂H₅)(HO₃SO)SiO_(1.0))₂]_(Σ8) (Formula10a)

A mixture ofexo-twisted-[(C₂H₅SiO_(1.5))₆((C₂H₅)(HO₃SO)SiO_(1.0))₂]_(Σ8) (Formula11a) and exo-[(C₂H₅SiO_(1.5))₆((C₂H₅)(HO₃SO)SiO_(1.0))₂]_(Σ8) (Formula10a) (1:3 ratio) was prepared in 27% yield by reacting[(C₂H₅SiO_(1.5))₈]_(Σ8) (Formula 2) (74.8 mg, 0.115 mmol) and coldH₂SO_(4/20)% SO₃ (45.3 mg, 0.389 mmol) at 25° C. for 30 min according tothe procedure described above for the synthesis ofexo-[(c-C₆H₁₁SiO_(1.5))₆((c-C₆H₁₁)(F₃CO₂SO)SiO_(1.0))₂]_(Σ8) (Formula10a).

CONVERSION OF FUNCTIONAL GROUPS AND MANIPULATION OF STEREOCHEMISTRYEXAMPLE 20 Method 1 Synthesis ofendo-[(c-C₆H₁₁SiO_(1.5))₆((c-C₆H₁₁)(HO)SiO_(1.0))₂]_(Σ8) (Formula 10b)

To a solution ofexo-[(c-C₆H₁₁SiO_(1.5))₆((c-C₆H₁₁)(F₃CO₂SO)SiO_(1.0))₂]_(Σ8) (Formula10a) (1.8 g, 1.33 mmol) in Et₂O (13 mL) was added triethylamine (0.281g, 2.777 mmol) at room temperature. After 15 min, the solution was addedwith vigorous stirring to a mixture of water (50 mL) and Et₂O (50 mL).The organic layer was immediately separated from the aqueous layer andfiltered through a small pad of anhydrous magnesium sulfate.Concentration of the solution to ca. 10 mL and addition of acetonitrileafforded a white precipitate, which was collected by filtration,dissolved in CH₂Cl₂ (150 mL) and reprecipitated with acetonitrile (50mL). Vacuum filtration and drying in air afforded 0.959 g of white solidcontaining endo-[(c-C₆H₁₁SiO_(1.5))₆((c-C₆H₁₁)(HO)SiO_(1.0))₂]_(Σ8)(Formula 10b) and [(c-C₆H₁₁SiO_(1.5))₆((c-C₆H₁₁)(HO)SiO_(1.0))₂]_(Σ8)(Formula 2) in a 97:3 ratio.

EXAMPLE 21 Method 1 Preparation ofendo-exo-[(c-C₆H₁₁SiO_(1.5))₆((c-C₆H₁₁)(HO)SiO_(1.0))₂]_(Σ8) (Formula10c)

To a mixture of Et₂O (3 mL) and water (3 mL) was added a solution ofexo-[(c-C₆H₁₁SiO_(1.5))₆((c-C₆H₁₁)(F₃CO₂SO)SiO_(1.0))₂]_(Σ8) (Formula10a) (72.6 mg, 0.053 mmol) and triethylamine (8.6 mg, 0.085) in Et₂O (3mL) with a vigorous stirring. After 5 min, the organic layer wasseparated and dried over MgSO₄; addition of CH₃CN (6 mL) and reductionof the volume to ca. 5 mL precipitated a white solid (yield 58 mg).Spectroscopic analysis indicate a mixture ofendo-exo-[(c-C₆H₁₁SiO_(1.5))₆((c-C₆H₁₁)(HO)SiO_(1.0))₂]_(Σ8) (Formula10c) (46%) and endo-[(c-C₆H₁₁SiO_(1.5))₆((c-C₆H₁₁)(HO)SiO_(1.0))₂]_(Σ8)(Formula 10b) (54%).

EXAMPLE 22 Method 21

A (13:87) mixture of [(c-C₆H₁₁SiO_(1.5))₆]_(Σ6) (Formula 1) andexo-[(c-C₆H₁₁SiO_(1.5))₄((c-C₆H₁₁)(F)SiO_(1.0))₂]_(Σ6)[(c-C₆H₁₁)₆Si₆O₈F₂](Formula 7) (300 mg) was reacted with excess Me₃SnOH (630 mg, 3.48 mmol)in refluxing CHCl₃ (30 mL) for 11 h. The volatiles were removed in vacuoto afford a white solid, which was redissolved in C₆H₆ (25 mL) andfiltered to remove particulate. After removing the solvent under vacuo,the solid was dissolved in CH₃Cl (15 mL) and stirred with a solution ofaqueous HCl (1.6 mL of I.2M). After 30 min, the mixture was dried overMgSO₄, filtered and evaporated (0.1 Torr) to afford an amorphous whitefoam, which was extracted with pyridine (1 mL, 30 min).([(c-C₆H₁₁SiO_(1.5))₆]_(Σ6) is insoluble in pyridine.) Careful additionof the pyridine extract to an ice-cold solution of HCl (2.5 mL ofconcentrated HCl and 2 mL of water) precipitated the disilanol, whichwas washed with water, extracted with CH₂Cl₂, dried over MgSO₄, andevaporated to affordexo-[(c-C₆H₁₁SiO_(1.5))₄((c-C₆H₁₁)(HO)SiO_(1.0))₂]_(Σ6)[(c-C₆H₁₁)₆Si₆O₈(OH)₂](Formula 7) as a white solid in quantitative yield based on availableexo-[(c-C₆H₁₁SiO_(1.5))₄((c-C₆H₁₁)(F)SiO_(1.0))₂]_(Σ6) (Formula 7).

EXAMPLE 23 Method 2 Synthesis ofExo-[(c-C₆H₁₁SiO_(1.5))₆((c-C₆H₁₁)(HO)SiO_(1.0))₂]_(Σ8) (Formula 10a)

Using the procedure described from the conversion of[(c-C₆H₁₁SiO_(1.5))₄((c-C₆H₁₁)(F)SiO_(1.0))₂]_(Σ6) (Formula 7) to[(c-C₆H₁₁SiO_(1.5))₄((c-C₆H₁₁)(HO)SiO_(1.0))₂]_(Σ6) (Formula 7) a 0.910g sample containingexo-[(c-C₆H₁₁SiO_(1.5))₆((c-C₆H₁₁)(F)SiO_(1.0))₂]_(Σ8) (Formula 10)(43%) and [(c-C₆H₁₁SiO_(1.5))₈]_(Σ8) (Formula 2) (57%) was reactedsequentially with Me₃SnOH (0.807 g) and 6N HCl (2 mL) in CHCl₃ (10 mL).After evaporating the majority of volatiles under reduced pressure (25°C., 1 Torr), the mixture was separated by flash chromatography on silicagel. (Both [(c-C₆H₁₁SiO_(1.5))₈]_(Σ8) (Formula 2) andexo-[(c-C₆H₁₁SiO_(1.5))₆((c-C₆H₁₁)(HO)SiO_(1.0))₂]_(Σ8) (Formula 12) aresoluble in pyridine.) Unreacted [(c-C₆H₁₁SiO_(1.5))₈]_(Σ8) (Formula 2)(511 mg) was eluted first with hexane. Subsequent elution with 1:1 (v/v)CH₂Cl₂/hexane afforded pureexo-[(c-C₆H₁₁SiO_(1.5))₆((c-C₆H₁₁)(HO)SiO_(1.0))₂]_(Σ8) (Formula 10a) asa white solid (268 mg, 68% based on available difluoride) afterevaporation (25° C., 1 Torr).

EXPANSION AND REDUCTION OF POSS SILICON-OXYGEN FRAMEWORKS EXAMPLE 24Preparation of [(c-C₆H₁₁SiO_(1.5))₈((CH₃)(H)SiO_(1.0))₁]_(Σ9) (Formula5)

Triethylamine (0.070 g, 0.691 mmol) and Cl₂Si(H)Me (0.029 g, 0.253 mmol)were added to a solution ofendo-[(c-C₆H₁₁SiO_(1.5))₆((c-C₆H₁₁)(HO)SiO_(1.0))₂]_(Σ8) (Formula 10b)(0.245 g, 0.223 mmol) in cold Et₂O (5 mL). (The sample ofendo-[(c-C₆H₁₁)₈Si₈O₁₁(OH)₂] contained 3% [(c-C₆H₁₁)₈Si₈O₁₂].)Precipitation of Et₃N.HCl began immediately, but the reaction wasstirred 4 h at 25° C. before filtration and concentration of thefiltrate to ca. 1 mL. Complete precipitation of Et₃N.HCl was induced byadding benzene (2 mL) and cooling to 0° C. Filtration of the resultingsolution through celite and evaporation (25° C., 1 Torr) afforded awhite solid. Pure [(c-C₆H₁₁SiO_(1.5))₈((CH₃)(H)SiO_(1.0))₁]_(Σ9)(Formula 5) was obtained in 76% yield (189 mg) by flash chromatography(SiO₂, hexanes, Rf=0.52).

EXAMPLE 25 Preparation of [(c-C₅H₉SiO_(1.5))₄((c-C₅H₉)(HO)SiO_(1.0))₃]_(Σ7) (Formula 13a)

In a typical reaction, 107 g (114 mmol) of[(c-C₅H₉SiO_(1.5))₇((Cl)SiO_(1.5))₁]_(Σ8) (Formula 6) is dissolved in800 mL of tetrahydrofuran (THF) and the solution is kept under nitrogen.To this well-stirred solution, an excess of LiAlH₄ (typically about 8 to10 grams) is added over about 30 minutes. After stirring for another 60minutes, the solution is filtered (in air) and the filtrate solventremoved under vacuum. The resulting solid is extracted with 500 mL ofwarm hexanes and the suspension filtered. The filtrate solution isreduced in volume under vacuum to form a slurry, that is then added to600 mL of well-stirred methanol. After several hours of stirring, themethanol-insoluble precipitate is collected by filtration to yield,after drying, 50-60 grams of [(c-C₅H₉SiO_(1.5))₇((H)SiO_(1.5))₁]_(Σ8)(Formula 3). The methanol-soluble filtrate is evaporated to dryness,then dissolved in 200 mL of THF and 100 mL of diethyl ether. Thissolution is twice washed with 100 mL of 1M aqueous HCl, followed bywashings with 100 mL of water and 100 mL of a saturated aqueous NaClsolution. The organic solution is dried over MgSO₄, filtered and thefiltrate solvent removed under vacuum. The solid is then extracted with50 mL of THF and the resulting slurry is added to approximately 200 mLof well-stirred acetone. After 1 hour of stirring, the precipitate iscollected by filtration to yield, after drying, 7-15 grams of[(c-C₅H₉SiO_(1.5))₄((c-C₅H₉)(HO)SiO_(1.O)) ₃]_(Σ7) (Formula 13a).Typical yields of the [(c-C₅H₉SiO_(1.5))₄((c-C₅H₉)(HO)SiO_(1.0))₃]_(Σ7)(Formula 13a) product range from 7 to 15%.

EXAMPLE 26 Preparation of[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁SiO_(1.0))₂((PhN)₁]_(Σ9) (Formula 19)

To a solution of [(C-C₆H₁₁SiO_(1.5))₆((c-C₆H₁₁)(TfO)SiO_(1.0))₂]_(Σ8)(Formula 10a) (159.0 mg, 0.117 mmol) and triethylamine (34.1 mg, 0.337mmol) in benzene (2 mL) was slowly added a solution of aniline (11.9 mg,0.128 mmol) in benzene (0.5 mL). After stirring the resulting emulsionfor 0.5 h at 25° C., the benzene layer was separated from the ammoniumtriflate by decantation. The oily ammonium triflate was rinsed twicewith benzene (0.5 mL). The organic layer were combined and the solventwas removed under reduced pressure. Precipitation from a mixture ofCHCl₃/CH₃CN affords [(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁SiO_(1.0))₂((PhN)₁]_(Σ9)as a white solid.

EXAMPLE 27 Preparation of[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁SiO_(1.0))₂((CH₃(CH₂)₃BO₂)₁]_(Σ9) (Formula20)

To a solution ofexo-[(c-C₆H₁₁SiO_(1.5))₆((c-C₆H₁₁)(F₃CO₂SO)SiO_(1.0))₂]_(Σ8) (Formula10a) (152.6 mg, 0.112 mmol) and triethylamine (60.8 mg, 0.601 mmol) inbenzene (3 mL) was slowly added a solution of butylboronic acid (27.9mg, 0.274 mmol) in benzene (0.5 mL). After stirring the resultingemulsion for 0.5 h at 25° C., the solvent was removed under vacuum andthe residue was dried under vacuum. The residue was redissolved inbenzene (1 mL). The benzene layer was separated from the ammoniumtriflate by decantation. The oily ammonium triflate was rinsed twicewith benzene (0.5 mL). The organic layer were combined and the volume ofthe solvent was concentrated to ca 1 mL. Addition of CH₃CN (10 mL)affords a precipitation of a mixture[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁SiO_(1.0))₂((CH₃(CH₂)₃BO₂)₁]_(Σ9) and[(c-C₆H₁₁SiO_(1.5))₈]_(Σ8) (81:19) (127 mg).

EXAMPLE 28 Preparation of[(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁SiO_(1.0))₂(CrO₄)₁]_(Σ9) (Formula 21)

A mixture ofendo-[(c-C₆H₁₁SiO_(1.5))₆((c-C₆H₁₁)(HO)SiO_(1.0))₂]_(Σ8)[(c-C₆H₁₁)₈Si₈O₁₁(OH)₂])(Formula 10b) (148 mg, 0.135 mmol), CrO₃ (133 mg, 1.330 mmol) and MgSO₄(371 mg) in CCl₄ (4 mL) was stirred for 48 h in the dark. Vacuumfiltration and evaporation of the volatile material under reducedpressure gave an amorphous orange solid, which was purified bychromatography using a short column of SiO₂ (dried under vacuum at 300°C.) and CHCl₃ as eluent to give[([(c-C₆H₁₁SiO_(1.5))₆(c-C₆H₁₁SiO_(1.0))₂(CrO₄)₁]_(Σ9)) as a brightorange solid in 55% yield.

Thus the present invention discloses methods that enable the selectivemanipulation of the silicon-oxygen frameworks in polyhedral oligomericsilsesquioxane (POSS) cage molecules. The methods of the inventionprovide for the selective ring-opening, stereochemical interconversion,expansion and reduction of POSS frameworks to form new families ofPOSS-related compounds.

Further the present invention teaches processes that enable themanipulation of the silicon-oxygen frameworks (the cage-like structure)of POSS-related compounds into new POSS species bearing frameworks withfunctionalities thereon for grafting, polymerization, catalysis or otherreactions.

What is claimed is:
 1. A method for controlling the stereo chemistry ofX groups to exo or endo positions on a polyhedral oligomericsilsesquioxane (POSS) compound comprising, adding reagents selected fromthe group consisting of a) CF₃SO₃H then H₂O, b) Me₃SnOH then HCl aq andc) HBF₄/BF₃ then Me₃SnOH then HCl aq to said X groups to change one ormore positions thereof to endo or exo, wherein said POSS compound is ofthe formula [(RSiO_(1.5))_(m)(RXSiO_(1.0))_(n)]_(Σ#), n=4-24, m=1-12,Σ=nanostructure, # is m+n, R is aliphatic, aromatic, olefinic, alkoxy,siloxy or H and said X groups are selected from the group consisting ofOH, OSO₂, CF₃, OSO₂, CH₃, F, Cl, I, Br, Me₃SnO, alkoxy, siloxy and Me₃is (CH₃)₃ and aq is aqueous.
 2. The method of claim 1 wherein an X groupcan change in kind as well as in said positions.
 3. The method of claim1 wherein


4. The method in claim 1 wherein


5. The method of claim 1 wherein


6. The method of claim 1 wherein


7. The method of claim 1 wherein


8. The method of claim 1 wherein


9. The method of claim 1 wherein


10. The method of claim 1 wherein

where method 1 is the hydrolysis of OSO₂CF₃ groups to a silanol specieswith inversion of stereochemistry as described in claim 1a) and method 3is the stereochemical change of position of OH groups as described inclaim 1c).
 11. A polyhedral oligomeric silsesquioxane (POSS) stereocompound of the formula [(RSiO_(1.5))_(m)(RXSiO_(1.0))_(n)]_(Σ#) wherem=4-24, n=1-12, #=m+n, R is aliphatic, aromatic, olefinic, alkoxy,siloxy or H and X is selected from the group consisting of OSO₂, CF₃,OSO₂, CH₃, F, Cl, I, Br, alkoxy and siloxy and Σ=nanostructure.
 12. APOSS compound selected from the group consisting of all formulas 7, 10 &11 and all a, b, c variants thereof shown in claims 3-10.
 13. The POSScompound of claim 11 selected from the group of difunctionalincompletely condensed [(RSiO_(1.5))₄(RXSiO_(1.0))₂]_(Σ6),tetrafunctional twisted [(RSiO_(1.5))₂(RXSiO_(1.0))₄]_(Σ6),tetrafunctional incompletely condensed[(RSiO_(1.5))₂(RXSiO_(1.0))₄]_(Σ6), difunctional twisted[(RSiO_(1.5))₆(RXSiO_(1.0))₂]_(Σ8), difunctional[(RSiO_(1.5))₅(R³SiO_(1.5))₁(RXSiO_(1.0))₂]_(Σ8) and their isomers whereR³ is selected from the same group as R but different from at least oneR.
 14. A method for inserting a ring substituent into a polyhedraloligomeric silsesquioxane (POSS) compound comprising, reacting[(RSiO_(1.5))_(m)(RXSiO_(1.0))_(n)]_(Σ#), with a reagent selected fromthe group of H₂NR, RB(OH)₂, K₂CrO₄, R₄NHSO₄, and H₂PR to obtain at leastone expanded POSS ring of[(RSiO_(1.5))_(m)(RSiO_(1.0))_(n)(E)_(j)]_(Σ#), where n is n is 1, 2 &4-24, m is 1-12, j is 1-8, # is m+n+j, R is aliphatic, aromatic,olefinic, alkoxy, siloxy or H, X is selected from the group consistingof OSO₂CF₃, OSNMe₃, OH, OSO₂Cl, OSO₂CH₃, OSO₃H, amine, and halide and Eis a ring substituent replacement for oxygen selected from the groupconsisting of NR, PR, CrO₄, SO_(4, O) ₂BR, O₂PR and O₂P(O)R andΣ=nanostructure.
 15. The method of claim 14 wherein R is selected fromthe group of alkyl, vinyl, allyl and phenyl and X is a halide or anamine selected from the group of NH₂, NHR and NR₂.
 16. The method ofclaim 14 wherein


17. The method of claim 14 wherein


18. The method of claim 14 wherein


19. The method of claim 14 wherein


20. A composition having at least one expanded ring in polyhedraloligomeric silsesquioxane (POSS) of the formula[(RSiO_(1.5))_(m)(RSiO_(1.0))_(n)(E)_(j)]_(Σ#), where # is m+n+j, R isaliphatic, aromatic, olefinic, alkoxy, siloxy or H, m is 1-12, n is4-24, j is 1-8 and E is a ring substituent replacement for oxygenselected from the group of NR, PR, CrO₄, SO₄, O₂BR, O₂PR and O₂P(O)R andΣ=nanostructure.
 21. The composition selected from the group consistingof formulas 19, 20 and 21 a & b shown in claims 16-19.